Analog Devices ADM8323/ADM8324 Supervisory Circuits monitor power supply voltage levels and code execution integrity in microprocessor-based systems. An on-chip watchdog timer checks for activity within a preset timeout window. A reset signal can also be asserted by an external push-button switch through a manual reset input. The RESET output is either push-pull (ADM8323) or open-drain (ADM8324). A watchdog failure results in a low output on the RESET pin. A failure can be triggered either by a fast watchdog error (watchdog pulses too close together) or by a slow watchdog error (no watchdog pulse within the timeout period). This effectively gives a window in which to observe the watchdog pulse. The watchdog timeout is measured from the last falling edge of the watchdog input (WDI). The ADM8323/ADM8324 are available in a 5-lead SOT-23 package and typically consume only 10μA, making them suitable for use in low power portable applications.